How to offset the edges?
Yes, you can.  Download and install the offset addon.  You can find the source code here:
https://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Modeling/offset_edges

You can find the compiled script (mesh_offset_edges.py) here: https://developer.blender.org/F100890

Put the file in your ..\Blender\2.xx\scripts\addons directory.  Then, in Blender, bring up User Preferences and click on the Addons tab.  At the bottom, click on "Install from file".  Find the file and click on it.